This invention relates to a selectively operable tool for use in wellbores to allow various operations to occur in formations surrounding a well. More specificially, this invention relates to a selectively operable tool to be installed in the casing in a wellbore to allow the surrounding formation at the location of the tool to be subjected to various operations through the tool with the tool being closed thereafter, thereby sealing the surrounding formation from producing into the casing.
In certain types of well cementing operations where it is desired to cement casing into a wellbore in stages, a selectively operable well cementing tool can be utilized to allow the flow of cement from the casing into the annulus surrounding the casing in the wellbore and then be closed to seal the flow of cement into the casing from the annulus. Such a prior art well cementing tool is shown in U.S. Pat. No. 3,768,562, issued to the assignee of the present invention. Another prior art version of this type well cementing tool where the movable sleeve is releasably retained within an initial position in tool is shown and described in U.S. patent application Ser. No. 183,416, filed Apr. 18, 1988, assigned to the assignee of the present invention.
Other types of well cementing tools which utilize cup-type packer elements in well cementing operations are shown and described in U.S. Pat. Nos. 2,546,978 and 2,672,199 and U.S. patent application Ser. Nos. 025,048, filed Mar. 12, 1987, assigned to the assignee of the present invention.
However, such prior art cementing tools are not generally suitable for use in wells where long sections of the formations surrounding the wellbore are to be treated, such as ten (10) feet or more, since they do not have sufficient flow area and ports therethrough. Also, such prior art cementing tools are not generally suitable for use in wells where portions of the wellbore are highly deviated having a short radius of deviation from the vertical portion of the wellbore since they are not resilient enough to be readily passed through the radius portion of the wellbore and, if forced, will be sufficiently damaged or deformed to prevent the sliding members of the tool remaining in or subsequent sealing engagement.